The Department of Biological Sciences at Stanford University requests funds from NIH to purchase a Philips EM410 transmission electron microscope (TEM) for our multi-user TEM facility. Our TEM facility is presently used by 11 laboratory groups from three different departments (Biological Sciences, Chemistry, Chemical Engineering) working in the areas of cell biology, developmental biology, immunology, neurobiology, genetics, biophysics, and molecular biology, with 4 more groups (Biological Sciences, Pediatrics), each with NIH support, wishing to use our new TEM, if and when it is available. Of the present 11 user groups, 9 are funded by 12 NIH research grants (in addition to other support). Our present TEM facility is the only one in the School of Humanities and Sciences on the Stanford Campus. We presently have only one TEM, a 13 year old Hitachi TEM, which is extremely unreliable (30% down time last year) and technically inadequate for our research needs. We request funds to purchase a new, high quality Philips TEM to meet the growing needs of our multi-user facility for a variety of research programs currently funded by NIH. We will provide the necessary facility in terms of space, personnel, and maintenance for this high quality TEM.